An American diplomat posed as a Korean tourist to investigate a notorious tiger breeding centre in southern China, where he saw animals whipped, made to perform "marriage processions" and reportedly sold to be used in traditional medicines.

As a result of the undercover visit to Xiongsen Tiger and Bear Farm, the US government was notified of doubts about China's conservation efforts, according to a diplomatic cable recently released by WikiLeaks.

The investigation – more a piece of journalism than spying – was inspired by a flurry of foreign media reports in the spring of 2007 alleging the farm offered tiger meat in its restaurant and tiger bone wine in a shop.

In a cable sent from the Guangzhou US consulate titled Devouring Dragon, Disappearing Tigers, an un-named economics officer (referred to as Econoff in the cable) said that he was initially treated with suspicion by the sales personnel in the facility. But once he convinced them he was Korean, they became eager to do business.

"The staff stated that up to three tour groups of Koreans came a day, numbering more than 30 in each group.The Koreans were among the most enthusiastic purchasers of both the black bear bile and the tiger wine." The price of the bottles ranged from 80-896 yuan.

The visitor to the farm – which has more than 1,000 tigers in its cages – described the spectacle of a tiger killing an ox in a "training cage" purportedly set aside as a training area for animals that are to be introduced to the wild. But most of the animals appear tame and some were used in circus-like entertainment shows, where they were beaten. Black bears – kept for their bile – were also made to join a mock Chinese marriage procession where they acted as bride and groom, he noted.

Locals told him that the farm served tiger meat and sold tiger skin, but this was denied by staff.

Nonetheless, he concludes in the cable dated 12 July 2007 that: "The commercial nature of the farm was troubling. The large number of endangered tigers and bears present with no current plans to reintroduce to them into the wild raises concern regarding the motivation of such a farm. Given the cost of feeding and caring for the numerous tigers, lions and bears, it appears highly unlikely that the farm would be able to meet its costs based solely on the admission price and government subsidies."

Four years on, these concerns remain valid. Reports earlier this year suggest the tiger population of the farm has grown and that budget problems mean many tigers lack food.

The diplomat also visited Longyan tiger reserve outside of Xiamen in Fujian province, where he found no signs of research activites – the stated purpose of the facility.